This invention relates to circuit breaker, and, more particularly, to a circuit breaker rotary contact arm arrangement.
Circuit breakers having a current interrupting module within a rotary contact arm arrangement whereby the circuit breaker movable contact arms are arranged at the opposite ends of the movable contact carrier are able to interrupt circuit current at a faster rate than circuit breakers having a movable contact carrier with a contact arranged at one end. U.S. Pat. No. 5,310,971 entitled Rotary Contact System for Circuit Breakers, describes a rotary contact arm that employs rollers between the contact springs and the contact arm to provide a uniform force distribution between the fixed contacts attached to the circuit breaker line and load straps and the movable contacts arranged at the opposite ends of the movable contact arm. One problem associated with a non-uniform force distribution between the fixed and movable contacts is the possibility of excessive contact erosion on the pair of contacts at the lower force points along the fixed contact surface.
U.S. patent application Ser. No. 09/384,908 filed Aug. 27, 1999 entitled Rotary Contact Assembly For High Ampere-Rated Circuit Breakers describes connecting the circuit breaker contact springs with the movable contact arm by means of pivotally-arranged links to compensate for contact wear and erosion over long periods of extensive circuit interruption.